“Shielded mild detonating cord” (SMDC) is used extensively in military aircrew escape systems. Typically, an SMDC consists of an extruded metal tube containing a central core of explosive material held in place by a sleeve. Both ends of the tube are fitted in an externally-threaded housing that has an explosive tip protruding therefrom. On one end of the SMDC, the tip is used as an acceptor charge for propagating a detonation wave from another device down the tube, while the other end acts as a donor charge for transferring the detonation wave to another device that can be another SMDC line. With this design, adjacent SMDC lines are explosively compatible thereby ensuring correct propagation of the detonation wave from one line to another.
Currently, a plastic cap is secured on the opposing end tips of each SMDC line to protect the tip from damage during shipping, handling, and storage. However, this shipping cap cannot contain the products of detonation of the hexanitrostibene (HNS) Type I transfer and booster charges contained in the tip. Thus, there is a substantial risk of fire and initiation of other explosives in the area should an inadvertent initiation occur while the plastic cap is in place. For these reasons, the United States Department of Defense's Ammunition and Explosives Hazard Classification Procedures require that SMDCs be packaged and shipped as Class 1 explosive articles. However, this designation considerably increases shipping, handling, and storage costs of SMDCs.